Maybe tell us the purpose, then we consider how sensible is that. Anyway, Icecast should be the solution. But we also need source client for Icecast. I don't really know the one capable of encapsulating and streaming Ogg-FLAC. Those provided by Xiph.org (ices and ezstream) don't seem to support FLAC.

I guess the more interesting question is whether you can do it under a bunch of constraints (on the hardware used on both ends, on your budget, etc.). On both the server and the client side, there are a lot more devices that can handle MP3 than FLAC. So again, the question becomes whether you can go with FLAC under constraints on your setup.

Yes, Google is a good way to learn something. But I do not find too much useful materials for me to understand how to stream a flac file. Maybe, the searching method I used is not so smart.

1. actually there is a well-known music player which can play not only normal mp3/aac lossy music, but also can play ape/flac lossless music files. So, playing software in the user side is not the problem. Besides, our first goal is to satisfy the users of us who have installed our pc/mobile music software.2. budget is not the problem neither. Cause we kind of have the proper CDN network, server sources, etc, there is no much extra money to be spent for streaming flac file specifically.Finally, what we have to face to is how to make the flac streaming work!

I really hope there is a reference example for me to do this thing. Maybe, some one of you can leave me some hints for doing this. Thanks.